add node modules to repo

app/node_modules/fs-extra/lib/util/assign.js

@@ -0,0 +1,14 @@
+// simple mutable assign
+function assign () {
+  var args = [].slice.call(arguments).filter(function (i) { return i })
+  var dest = args.shift()
+  args.forEach(function (src) {
+    Object.keys(src).forEach(function (key) {
+      dest[key] = src[key]
+    })
+  })
+
+  return dest
+}
+
+module.exports = assign